/**
 * Accessibility CSS
 * 提供无障碍访问相关的样式
 */

/* 跳过导航链接 - 允许键盘用户跳过导航 */
.sk-skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary-color);
  color: #000;
  padding: 8px;
  z-index: 9999;
  transition: top 0.3s;
}

.sk-skip-link:focus {
  top: 0;
}

/* 焦点样式 - 为键盘用户提供清晰的焦点指示 */
:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* 隐藏仅供屏幕阅读器使用的内容 */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 减少动画 - 为有前庭障碍的用户减少动画效果 */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

.sk-reduce-motion * {
  animation-duration: 0.01ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.01ms !important;
  scroll-behavior: auto !important;
}

/* 高对比度模式 */
@media (prefers-contrast: more) {
  :root {
    --primary-color: #ffff00;
    --bg-color: #000000;
    --text-color: #ffffff;
    --secondary-text: #ffffff;
    --card-bg: #333333;
  }
  
  .sk-card,
  .sk-footer,
  .sk-header {
    border: 1px solid #ffffff;
  }
  
  .sk-card__title a,
  .sk-footer__link,
  .sk-nav__link {
    text-decoration: underline;
  }
}

/* 更大的点击/触摸区域 */
button,
.sk-btn,
.sk-nav__link,
.sk-footer__link,
.sk-user-actions__btn {
  min-height: 44px;
  min-width: 44px;
}

/* 改进表单元素的可访问性 */
input,
textarea,
select {
  font-size: 16px; /* 防止iOS上的缩放 */
}

input[type="checkbox"],
input[type="radio"] {
  width: 20px;
  height: 20px;
}

/* ARIA状态样式 */
[aria-expanded="true"] .sk-dropdown__icon {
  transform: rotate(180deg);
}

[aria-hidden="true"] {
  display: none;
}

/* 无障碍模式切换按钮 */
.sk-accessibility-toggle {
  position: fixed;
  bottom: 20px;
  left: 20px;
  width: 44px;
  height: 44px;
  background: rgba(0, 0, 0, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 999;
  cursor: pointer;
}

.sk-accessibility-toggle i {
  color: #ffffff;
  font-size: 24px;
}

/* 无障碍模式样式 */
body.sk-accessibility-mode {
  font-size: 18px;
  line-height: 1.8;
}

body.sk-accessibility-mode .sk-container {
  max-width: 1000px;
}

body.sk-accessibility-mode .sk-card__title,
body.sk-accessibility-mode .sk-section__title,
body.sk-accessibility-mode .sk-footer__title {
  font-size: 1.5em;
}

body.sk-accessibility-mode .sk-nav__link,
body.sk-accessibility-mode .sk-footer__link,
body.sk-accessibility-mode .sk-btn {
  font-size: 1.2em;
  padding: 12px;
}

/* 图片替代文本指示器 */
img:not([alt]),
img[alt=""] {
  border: 3px solid red;
}

/* 键盘导航辅助 */
.sk-keyboard-nav {
  display: none;
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: rgba(0, 0, 0, 0.8);
  color: white;
  padding: 10px;
  border-radius: 5px;
  z-index: 9999;
  font-size: 14px;
}

body.sk-keyboard-navigation .sk-keyboard-nav {
  display: block;
}

/* 检测键盘导航 */
body:not(.sk-using-mouse) *:focus {
  outline: 3px solid var(--primary-color) !important;
  outline-offset: 3px !important;
}

/* Focus Indicators */
*:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
  border-radius: 2px;
}

button:focus-visible,
.sk-btn:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 3px;
}

/* High Contrast Support */
@media (prefers-contrast: high) {
  :root {
    --primary: #ffff00;
    --bg-primary: #000000;
    --bg-secondary: #1a1a1a;
    --text-primary: #ffffff;
    --border-color: #ffffff;
  }
  
  .sk-card {
    border: 2px solid var(--border-color);
  }
  
  .sk-btn {
    border: 2px solid currentColor;
  }
}

/* Screen Reader Only Content */
.sr-only:focus {
  position: static;
  width: auto;
  height: auto;
  padding: inherit;
  margin: inherit;
  overflow: visible;
  clip: auto;
  white-space: inherit;
}

/* Focus Management for Modals */
.modal-open {
  overflow: hidden;
}

.modal-open .sk-main,
.modal-open .sk-header,
.modal-open .sk-footer {
  filter: blur(2px);
  pointer-events: none;
}

/* Better Link Indicators */
a:not(.sk-btn):not(.sk-card):not(.sk-header__logo-link) {
  text-decoration-line: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

a:not(.sk-btn):not(.sk-card):not(.sk-header__logo-link):hover {
  text-decoration-thickness: 2px;
}

/* Form Accessibility */
.form-error {
  color: #ff4444;
  border-color: #ff4444;
}

.form-error:focus {
  outline-color: #ff4444;
}

.error-message {
  color: #ff4444;
  font-size: var(--font-sm);
  margin-top: var(--space-xs);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.error-message::before {
  content: "⚠️";
  flex-shrink: 0;
}

/* Loading States */
.loading {
  position: relative;
  pointer-events: none;
}

.loading::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  margin: -10px 0 0 -10px;
  border: 2px solid transparent;
  border-top: 2px solid var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Color Blind Support */
.success {
  background-color: #28a745;
  position: relative;
}

.success::before {
  content: "✓";
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
}

.error {
  background-color: #dc3545;
  position: relative;
}

.error::before {
  content: "✗";
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
}

.warning {
  background-color: #ffc107;
  color: #000;
  position: relative;
}

.warning::before {
  content: "⚠";
  position: absolute;
  left: 8px;
  top: 50%;
  transform: translateY(-50%);
}

/* Interactive Element Sizing */
@media (pointer: coarse) {
  button,
  .sk-btn,
  a,
  input,
  select,
  textarea {
    min-height: 48px;
    min-width: 48px;
  }
}